People who experience considerable dread about an adverse experience can be distinguished biologically from those who tolerate the experience better, said researchers in May 5 issue of the journal Science.
In the first brain imaging study of dread, Gregory S. Berns, MD, PhD, associate professor, Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, and colleagues used functional magnetic resonance imaging (fMRI) to create images of brain activity in 32 participants who were awaiting brief electrical shocks to their feet. (fMRI technology charts which regions of the brain experience increased blood flow over time, which helps scientists understand the relationship between particular types of mental activity and specific areas of the brain.)
The study researchers observed that brain activity patterns associated with the dread of waiting involved areas of the brain that govern human pain perception. Specifically, they saw responses in brain areas that appear to be ruled by attention more than regions associated with fear.
Researchers determined each participant’s maximal pain threshold and gave them a series of choices from 36 possibilities. For example, each participant could elect to receive a shock that was 30 percent of his or her pain threshold in 27 seconds or one that was 60 percent of the threshold in nine seconds.
"We noted that normal, healthy subjects could be divided into two groups—extreme dreaders who could not tolerate a delay and preferred an immediate (and stronger) painful stimulus, and mild dreaders who could tolerate a delay for a milder shock," said Dr. Berns. "We saw that the extreme dreaders could be distinguished from the mild dreaders by virtue of the information captured on the brain scans. The findings suggest that dread derives, in part, from the attention devoted to the expected physical response and is not simply a fear or anxiety reaction."
The study was supported by the National Institute on Drug Abuse, National Institutes of Health.
